grasshopper645
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- Jan 15, 2012
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- New Zealand
- Members Ride
- 2006 VZ SS Ute 6.0
More interestingly, what protocol are missing on VXDIAG which won’t allow it to be used on pre 2007 Holdens?
Here is a pin out of OBD2 connector with its various protocol flavours
View attachment 224341
https://www.pinterest.com.au/pin/423549539957070190/?d=t&mt=login
If you open up the vxdiag unit, you will see pin9 does not have any printed traces going out to anything. So it's never going to work.
Also 2007 and before (approx) are NOT obd2, only the ECM is obd2 compliant. All of the communications are done on obd1 data bus. In fact, the ECM communicates to the rest of the modules over obd1. The PIM converts the packets from obd2 to obd1 to be sent to the rest of the modules (SDM, EBCM, ABS, etc)
Your obd2 diagrams in this post are not relevant as none of them are used. A tech2 unit connected to the obd2 port on a vz and prior holden is actually using GM uart (a Proprietary connection over ob1. Thats why none of your cheap bluetooth scan tools will be of any use to pull abs, airbag, or bcm related codes. Because they can't interface with the car at all.
If you can get one cheap enough, the vxdiag is ok as you can use it to interface with ecm functions and do bi-directional features like CPS relearn, actuate transmission solenoids, etc, but its definitely NOT worth spending money on them for the above reasons.